package org.oslims.client.uicomponents;

/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

import com.google.gwt.cell.client.CheckboxCell;
import com.google.gwt.cell.client.FieldUpdater;
import com.google.gwt.user.cellview.client.Column;
import com.google.gwt.view.client.SelectionModel;

/**
 * A column that displays a checkbox that is synchronized with a given selection
 * model.
 * 
 * @param <T>
 *            the record data type, used by the row and the selection model
 */
public class SelectionColumn<T> extends Column<T, Boolean> {

	private final SelectionModel<T> selectionModel;

	public SelectionColumn(final SelectionModel<T> selectionModel) {
		super(new CheckboxCell());
		setFieldUpdater(new FieldUpdater<T, Boolean>() {
			public void update(int index, T object, Boolean value) {
				selectionModel.setSelected(object, value);
			}
		});
		this.selectionModel = selectionModel;
	}

	@Override
	public boolean dependsOnSelection() {
		return true;
	}

	@Override
	public Boolean getValue(T object) {
		return object != null && selectionModel.isSelected(object);
	}
}
